I am wondering if there is some sort of connector/device I can use to connect to my iPod/iPhone-connector on my stereo, so that I can use this device as a 'receiving station' for my i-device?

Why? I would like to use my radio as music player for my iPod/iPhone. However, I constantly have to walk and control from the device connected to it, while I think it can be done wirelessly and by means of some sort of connector/dock.
In such a way that I can use my iPod/iPhone as remote - via WiFi - to connect to my stereo set.

Does such a device/connector exist? And which brand?

EDIT:
I can get some SONOS device, but I'm looking for a cheaper alternative.